1. Technical Field
The present invention relates to a polarizing element, a polarizing element manufacturing method, a liquid crystal device, and a projection display.
2. Related Art
A liquid crystal device is used as an optical modulation device in a projection display, such as a projector. Known as such liquid crystal devices are those in which a liquid crystal layer is interposed between a pair of substrates disposed to face each other. In these liquid crystal devices, electrodes for applying a voltage to the liquid crystal layer are formed between the pair of substrates. Alignment layers for controlling the alignment of liquid crystal particles when a voltage is not applied are formed between these electrodes. Known as such alignment layers are those in which the surface of a polyimide film is subject to rubbing.
On the other hand, a polarizing plate is disposed outside each of the pair of substrates (on the surfaces remote from the surfaces that face the liquid crystal layer) so that predetermined polarized light enters the liquid crystal layer. Known as such a polarizing plate is a polarizing film manufactured by extending a resin film made of an organic compound in one direction and thus orienting iodine or dichroic dye in a predetermined direction. Also known is a wire grid polarizing plate in which a grid made of a metal is laid over a transparent substrate (glass substrate). The most remarkable feature of such a wire grid polarizing plate is that the polarizing plate has excellent durability because it is made of an inorganic material. As such a wire grid polarizing plate, technologies such as JP-A-2003-519818 and JP-A-2002-520677 are disclosed.
Recently, a technology has been proposed that incorporates a wire grid polarizing plate into a liquid crystal panel rather than using it as a single unit. Such incorporation of a polarizing element greatly helps reduce parts count or enhance the functionality of a liquid crystal panel. Incidentally, it is known that the optical characteristic of a wire grid polarizing element is influenced by a material interposed between grid cells (conductors), and a material whose index of refraction is 1, that is, air (or vacuum atmosphere) is preferably interposed between the grids cells.
The above-mentioned JP-A-2003-519818 focuses attention on a material between such grid cells and can seal air (or vacuum) between the grid cells. However, if the polarizing element disclosed in JP-A-2003-519818 is disposed in a cell, a cover glass must be provided in only a pixel region. Further, the disposition of the cover glass increases the thickness of the cell. These significantly reduce the feasibility of such disposition. Also, JP-A-2003-519818 does not mention a specific manufacturing method. While a technology for incorporating a wire grid polarizing element is disclosed in JP-A-2002-520677, use of the technology may reduce the optical characteristic because a planarizing layer is embedded between grid cells.